import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import java.util.concurrent.RecursiveTask;

class MyTask extends RecursiveTask<Integer> {
    private static final Integer ADJUST_VALUE = 10;

    private int begin;
    private int end;
    private int result;

    public MyTask(int begin, int end) {
        this.begin = begin;
        this.end = end;
    }
    @Override
    protected Integer compute() {
        if ((end - begin) <= ADJUST_VALUE) {
            for (int i=begin;i<= end;i++){
                result = result + i;
            }
        } else {
            int middle = (end + begin)/2;
            MyTask task1 = new MyTask(begin, middle);
            MyTask task2 = new MyTask(begin, middle);
            task1.fork();
            task2.fork();
            result = task1.join() + task2.join();
        }
         return result;
    }
}



/**
 * 分支合并框架
 */
public class ForkJoinDemo {
    public static void main(String[] args) throws Exception{
        MyTask myTask = new MyTask(1, 100);
        ForkJoinPool threadPool = new ForkJoinPool();
        ForkJoinTask<Integer> forkJoinTask = threadPool.submit(myTask);
        System.out.println(forkJoinTask.get());
        threadPool.shutdown();
    }
}
